The Cross City Tunnel is Sydney's first cashless toll road, following the precedent set by Melbourne's Citylink in 2000. The two two-lane tunnels run between the Western Distributor in the vicinity of Harbour St at Darling Harbour and New South Head Road at Rushcutters Bay. Some entry and exit movements are also permitted in an underground interchange with the Eastern Distributor tunnels at Darlinghurst.

Eastbound traffic can enter the tunnel from the Western Distributor (via the right lane on the Bathurst St offramp) and Harbour Street (northbound) and travel beneath Bathurst St, Hyde Park and William St. Eastbound traffic may then exit via a loop ramp to the Eastern Distributor southbound or continue east in the main tunnel to surface onto Bayswater Rd at Rushcutters Bay.

Westbound traffic enters the tunnel at the eastern portal of the Kings Cross Tunnel (near Ward St), Darlinghurst, and also from the Eastern Distributor northbound (via the William St offramp and toll booths). The tunnel then proceeds directly west beneath William, Park and Druitt Streets to surface where the westbound carriageway of the Western Distributor hits ground level before crossing Harbour Street. Westbound traffic can either exit straight onto the Western Distributor (no access to Harris St) or onto Harbour St. Also, westbound traffic may exit the tunnel to go to either the Harbour Bridge or Tunnel via a ramp that surfaces on Sir John Young Crescent.

Also part of the Cross City Tunnel project are the upgrade of William Street and the construction of a new bus lane from the Western Distributor to Druitt Street. William Street will be narrowed to two lanes in both directions (one lane in each direction will be a daytime T2 lane) and the footpaths will be widened with new tree plantings. Druitt Street will have some radical changes. A new eastbound bus crossover will be built between the Western Distributor above Harris Street and the Druitt Street viaduct, with the 24 hour bus lane extending east along Druitt Street as far as George Street. Druitt will become a two-way bus-only street between Kent St and Clarence St, but will have one westbound lane between Kent St and the Western Distributor. This means that any traffic heading west in Druitt St from George St must use Clarence and Market Streets to reach the Western Distributor! Damn this is confusing.... But luckily, Davis Griffin has saved the day with THIS wonderful diagram of how the lanes will look on Druitt Street. Note the red lines are the bus lanes.